In the cutting of sheet material, particularly limp sheet material such as cloth or leather in an automated cutting system, it customary to generate a marker which indicates the shapes and arrangements of parts to be cut from a section of the sheet material. The marker is often generated by a computer program and displayed on a monitor for operator modification or adjustment prior to cutting the sheet. The information in the marker is then used to create a set of instructions usable by a cutting system. Once the parts are cut from the sheet material, the parts must be removed and presented for subsequent processing.
To identify the cut pieces for subsequent handling and/or assembly, the prior art has employed labelers for affixing labels to the sheet material such as shown by U.S. Pat. Nos. 4,028,167; 4,189,377; and 4,514,246. More recently, U.S. Pat. Nos. 5,141,572 and 5,092,829 disclose labelling and bundling mechanisms.
Alternatively, as shown in U.S. Pat. No. 3,895,358 a paper plot of the part peripheries is printed on plotter paper and the paper is placed on the fabric before cutting. The top layer of the paper remains attached to the parts so that the operator can identify and pass the parts to a corresponding subsequent process.
While the prior systems identify the cut parts, the systems are relatively complicated and require a substantial investment in hardware or materials. In addition, for those subsequent processes where members of a specific subset have been placed in a common area and further identification of the individual members of the subset is unnecessary, the prior labelling methods are redundant, or provide excessive labelling.
Therefore, the need exists for a method and apparatus of non-intrusively and temporarily identifying cut parts while in their cut position on a sheet material as well as their association with a specific subset for subsequent handling or processing. The need further exists for identifying the cut parts that are members of a particular subset, wherein the subset members may be located in different sheets or sections of the sheet. The need also exists for identifying the cut parts to provide a sorting which expedites downstream processing.